Easy calculator



Dec. 2, 1969 N. F. WELCH 3,481,537

EASY CALCULATOR Filed Jan. 8, 1968 /Z n---- TO SUBTRACT TO ADD I NVENTOR.

Ivor/nan F7 oyd We/c/I United States Patent 3,481,537 EASY CALCULATORNorman Floyd Welch, 50490 La Gae, New Baltimore, Mich. 48047 Filed Jan.8, 1968, Ser. No. 696,182 Int. Cl. G06c 27/00 U.S. Cl. 235-69 4 ClaimsABSTRACT OF THE DISCLOSURE A calculator for arithmetical calculations isdisclosed comprising a case containing a plurality of round dowels sideby side with their axes disposed in a common plane, the dowels aremoveable in respect to the case, the case bearing indicia used inconjunction with the movement of said dowels for said arithmeticalcalculations, the dowels commonly visible in respect to the indicia onthe case, each dowel both axially slidable and rotatable in respect tosaid case.

The present invention while relating broadly to calculating devices ingeneral, has more particular reference to a relatively small and compactmanually operable instrument that can be carried in a pocket or purseand thus be readily accessible for use at all times, the main objectiveof the invention being the provision of a calculator of the characterdescribed particularly adapted for use by engineers, draftsmen andothers, whereby answers to arithmetical calculations in addition,subtraction, multiplication and division may be quickly and easilyobtained and visually indicated.

Another object of the invention is to provide a simple calculatingdevice which will not only be attractive and interesting to children buta valuable aid in learining addition, subtraction and, particularly, themultiplication tables.

A further and important object of the invention is the provision of acalculating device of but few parts which is of durable and practicalconstruction, inexpensive to manufacture and not liable to derangement.

Other objects and advantages of the invention will become apparent froma consideration of the following detailed description taken inconnection with the accompanying drawing wherein a satisfactoryembodiment of the invention is shown. However, it is to be understoodthat the invention is not limited to the details disclosed but includesall such variations and modifications as fall within the spirit of theinvention as defined herein.

In the drawing:

FIGURE 1 is a top plan view of an easy calculator embodying theinvention;

FIGURE 2 is a right side view of said embodiment;

FIGURE 3 is a fragmentary view of said embodiment with parts in section;said view being generally as taken on the line 33 of FIG. 2;

FIGURE 4 is a top plan View of said embodiment shown broken into top andbottom portions; the dowels in the top portion being arranged foraddition or subtraction and in the bottom portion for multiplication ordivision.

The easy calculator comprises, in the instance shown, nine dowels 5preferably of equal length and arranged side by side in a row in thepocket 6 formed within a rectangular case generally indicated at 7. Thepocket ed or otherwise secured to the flanges 11 is a cover plate 12 oftransparent plastic. The term dowel as used herein includes in itsmeaning any cylindrical rod.

When not in use all of the dowels 5 have their contained ends bottomingagainst or abutting the end wall 10 of the case 7. The free ends of thedowels 5 extend beyond the open end of the case 7 to provide fingerengaging portions for manipulation of the dowels by the hand of theperson using the easy calculator. The dowels 5 are capable of both axialsliding and rotational movement within the pocket 6.

The surface of cover 12 is preferably provided with axially spacedtransverse hairlines 14. A horizontal row of numbers from 0 to 9 isvisible along the upper edge of the cover plate 12 above the dowels 5which are used in addition and subtraction. Another horizontal row ofnumbers from 1 to 9 is visible along the lower edge of the cover plate12 below the dowels 5 which are used in multiplication and division.

Each of the dowels 5 bear nine numbers on its top surface which arevisible through the cover plate 12. The first number on the uppermost orfirst dowel (as viewed in FIG. 1) is 1 and the nine numbers thereon areseparated in numerical quantity by 1; the first number on the seconddowel is 2 and the nine numbers thereon are separated in numericalquantity by 2; this arrangement is repeated down to the lowermost orninth dowel, the first number of which is 9 and the nine numbers thereonare separated in numerical quantity by 9. The dowels 5, takencollectively, thus have the multiplication tables 1 through 9 printedthereon as shown. Each dowel 5 has axially spaced transverse notches 15(see FIGURE 3) adapted toreceive in holding engagement a V-shaped tooth16 on a spring arm 17 secured by a rivet 18, or other means, to thebottom 8 of casing 7. This arrangement yieldably holds the dowelswherever they are positioned in said pocket against axial slidingmovement.

To facilitate reading of the results in multiplication every othertransverse row of numbers on the dowels is preferably provided with acolored background such as a red background.

The following paragraph is an explanation of ,use of the easy calculatorin addition:

In addition and subtraction the dowels are turned down, that is, rotatedso that the numbers thereon are not visible through the cover plate 12.The uppermost or first dowel represents the UNITS place; the seconddowel the TENS place; the third dowel the HUNDREDS place, etc. Thedowels are axially slid from left to right (as viewed in the upperportion of FIG. 4) in addition and from right to left in subtraction.The upper portion of FIG. 4 illustrates the quantity 71 by the positionsof the second and first dowels, respectively, the contained ends ofwhich are indicated in dotted lines and shown disposed beneath 4 areshown and indicated in full lines.

6 is rectangular in transverse cross-section and the axes of I Thefollowing paragraph is an explanation of the use of the easy calculatorin multiplication and division:

The lower portion of FIG. 4 shows the four lowermost dowels set up withthe number 9876 ready for multiplication by the multipliers 2 through 9in the bottom row. The leftmost number (in this case 9) is set up on thelowermost dowel to the extreme left of the pocket and the next number(in this case 8) is set up on the second lowermost dowel displaced onedigit to the right and so on to the units number (in this case 6). Theproduct 19752 of the multiplier 2 can be seen in FIG. 4; (this product19752 can be seen in FIG. 4 if the viewer mentally adds the staggerednumbers 18, 16, 14 and 12 above the multiplier 2) likewise the product29628 of the multiplier 3; likewise the product 39504 of the multiplier4; and so on to the product 88884 of the multiplier 9.

In multiplication the multiplicand and in division the divisor is thusset up on the dowels in staggered fashion to the right as shown in FIG.4 for the number 9876.

For an example of the use of the calculator in multiplication, assumethat 987.6 must be multiplied by 8.79. The product of 9876 as themultiplicand with the multiplier 9 is read off the calculator as shownin FIG. 4 to be 88884 and written on paper under the line beneath 8.79with the 4 of 88884 beneath the 9 of 8.79. The product of 9876 with themultiplier 7 is next read off the calculator as shown in FIG. 4 to be69132 and written on paper beneath 88884 but shifted one digit to theleft in the usual manner. The product of 9876 with the multiplier 8 isthen read off the calculator as shown in FIG. 4 to be 79008 and writtenon paper beneath 69132 but shifted one digit to the left in the usualmanner. The three separate products are then added in the usual manneron paper to obtain the final product 8681.004.

The calculator is used in division to assist in finding the correctquotient more quickly. For example, assume that 241,962 must be dividedby 9876. The divisor 9876 is set up on the dowels as shown in the lowerportion of FIG. 4. The first step is to find the correct first digit ofthe quotient which is seen to be 2 since the product of the multiplier 2with the divisor 9876 is seen in FIG. 4 to be 19752 which is the closestproduct less than 24196. (The product of the multiplier 3 with thedivisor 9876 is seen in FIG. 4 to be 29628 and hence too large for 3 tobe the first digit of the quotient.) The first subtraction step in thedivision is carried out on paper resulting in 44442 (2 carried from thedividend) and the second digit of the quotient is sought and found to be4 since the product of the multiplier 4 with the divisor 9876 is seen inFIG. 4 to be 39504 which is the closest product less than 44442. (Themultiplier 5 yielding a product of 49380 is seen to be too large.) Thesecond subtraction step in the division is carried out on paperresulting in 493 80 carried from the dividend after placing the decimalpoint after 241,962) and the third digit of the quotient is sought andfound to be since the product of the multiplier 5 with the divisor 9876is seen in FIG. 4 to be 49380. Consequently the correct quotient is24.5. v

In conclusion it may again be stated that cover 12 has hair lines andnumbers, as shown in plan view, and that the dowels 5 (1 thru 9) havemultiplication tables printed thereon, also as shown, that they arenotched diametrically opposite the number so as to make positioning ofthe dowels fast in adjusted positions thereof in the manner set forth.

In addition and subtraction the dowels representing UNITS, TENS,HUNDREDS, etc. as required, are turned down so that the numberingthereon does not show. In addition the dowels are moved from left toright. In addition when a dowel is moved to the extreme left (i.e. thecontained end of the dowel is moved beneath zero in the top row ofnumbers) the dowel beneath (as viewed in FIGS. 1 and 4) must be movedone number to the right.

For example:

6+6=12. Move #1 dowel from beneath the number 6 v4 5-+1+1=7. Move #3dowel from beneath the number 5 to the right to beneath the number 7.

To subtract the dowels are moved from right to left. In subtraction whena dowel is moved to the extreme right (i.e. the contained end of thedowel is moved beneath the number 9 in the top row of numbers) the dowelbeneath (as viewed in FIGS. 1 and 4) must be moved one number to theleft.

For example:

126=6. Move #1 dowel from beneath the number 2 to the extreme left tobeneath the number zero and then to the extreme right to beneath thenumber 9 and then to the left to beneath the number 6.

13 14=8. Move #2 dowel from beneath the number 3 to the extreme left tobeneath the number zero and then to the extreme right to beneath thenumber 9 and then to the left to beneath the number 8.

715=1. Move #3 dowel to the left from beneath the number 7 to beneaththe number 1.

To multiply, the first figure of any number must be at the extreme leftend of the case 7.

What I claim is:

1. A calculator for arithmetical calculations comprising a casecontaining a plurality of round dowels side by side with their axesdisposed in a common plane, said dowels moveable in respect to saidcase, said case bearing indicia used in conjunction with the movement ofsaid dowels for said arithmetical calculations, said dowels commonlyvisible in respect to said indicia on the case, each dowel both axiallyslidable and rotatable in respect to said case, said dowels bearingindicia on the top surfaces thereof used in multiplication and divisionand being blank on the bottom surfaces thereof for use in addition andsubtraction, said indicia on the case including along one side of theplurality of dowels a row of consecutive numbers used in addition andsubtraction when the dowels used in addition have been rotated to showtheir blank bottom surfaces, said indicia on the case further includingalong the opposite side of the plurality of dowels another row ofconsecutive numbers used in multiplication and division when the dowelsused in multiplication and division have been rotated to show theirindicia bearing top surfaces, said last-mentioned dowels bearing viasaid indicia on their top surfaces the multiplicand in multiplicationand the divisor in division.

2. A calculator as claimed in claim 1, and means for yieldably holdingthe dowels wherever they are positioned in respect to said case incarrying out said arithmetical calculations. v

3. A calculator as claimed in claim 1, said dowels being nine in number,said indicia on the top surfaces there of collectively comprising themultiplication tables from 1 through 9.

4. A calculator as claimed in claim 1, said case having a pocket thereinwith a blind end and an openend and top and bottom walls, said dowelscontained in said pocket and having free ends projecting out of saidopen end, said dowels individually insertable into and removeable fromsaid pocket and being moveable therein, the contained ends of saiddowels capable .of bottoming against said blind end, said case having acover plate, the cover plate for the case being the top wall of thepocket and being transparent so that the dowels are visibletherethrough. i a

References Cited UNITEDSTATES PATENTS (Other references on followingpage) 5 6 UNITED STATES PATENTS 625,045 4/1927 France. 11 1921 n 235 697 ,575 1/1918 Switzerland.

7/1940 Stern 3531 v 12/1950 Steward 235 69 RICHARD B. WILKINSON, PrlmaryExammer 12/1963 Collischonn 23569 5 STANLEY A. WAL, Assistant ExaminerFOREIGN PATENTS US. Cl. X.R.

9/1929 Australia. 116135 1/ 1923 Denmark.

